Manufacture of dibenzanthronyls



Patented May 5, 1931 UNITE SATES ARTHUR L TTTRINGHAUS AND HUGO VJOLFF, OF MANNI-IEIM, AND HEINRICH NERES- EEIMER, OF LUDWIGSHAFEN-ON-THE-BHINE, GERMANY, ASSIGNORS TO GENERAL ANILINE WORKS, INC., 03? NEVJ' YORK, N. Y., A GOREOB-A'I'ION OF DELAWARE MANUFACTURE OF DIBENZANTHRONYLS No Drawing. Original application filed June 5, 1926, Serial No. 114,011, and. in Germany June 15, 1925. Divided and this application filed January 25, 1930. Serial No. 423,538.

i5 responding to the general formula can be obtained by treating benzanthrone or its derivatives and analogues with alkaline condensing agents under more moderate conditions than those leading substantially to vat dyestufis.

We have now found that 2.2-dibenzanthronyl or its derivatives are also obtained by subjecting, instead of benzanthrones, a mixture of about molecular proportions of 2-l1alogen benzanthrone or its substitution products and benzanthrone or its derivatives, having a free 2-position, to condensation with alkaline condensing agents under moderate conditions.

While in the process described in the U. S. Patent No. 1,564,423, 2 molecules of benzanthrone are combined to 2.2'-dibenzanthronyl with the elimination of 2 atoms of hydrogen, according to the present invention 1 molecule of 2-halogen-benzanthrone combines with 1 molecule of benzanthrone with the elimination of 1 molecule of hydrogen halide. This In case small quantities of dyestuff are formed simultaneously with the 2.2-dibenzanthronyls, they may be extracted by treatment with an alkaline hydrosulphite solution.

The following examples will further illustrate how our present invention can be carried out in practice but the invention is not limited to these examples. The parts are by weight. 1

Ewam-ple 6 parts of sodium are dissolved in 400 parts of anhydrous aniline in the presence of a small quantity of nickel oxide by heating and the resulting mixture is then cooled. The liquid now contains 30 parts of sodium anilide, partly in a dissolved state and partly in a state of suspension. A mixture of 20 parts of pure benzanthrone and 23 parts of 2- chlor-benzanthrone (melting at 204 C.) is introduced at 5 G. into the said suspension in a current of nitrogen. The temperature is hereby raised to 11 C. The color of the reaction mixture which is brownish yellow in the beginning, turns gradually reddish brown. The mixture is stirred for some hours at 11 to 12 C. while introducing nitrogen. It is then mixed with dilute hydrochloric acid and filtered. The residue remaining on the filteris treated with hot acetone until practically all soluble matter is dissolved. The crude 2.2-dibenzanthronyl so obtained can be purified by recrystallization from xylene or chlorbenzene. It is identical with the product described in Example 1 of the U. S. Patent No. 1,564,423.

The temperature at which the reaction is carried out may be varied within wide limits; for example, 2.-2-dibenzanthronyl'is formed with a good yield and without formation of of nitrogen into a suspension of 15 parts of sodium anilide in 200 parts of anhydrous aniline. The temperature is raised thereby 1 acid with red color. It can be purified by recrystallization from boiling xylene whereby it is obtained in the form of glittering leaflets meltingat 328 C. It is 6methyl-2.2idibenzanthronyl.

Example 3 lVhen carrying out the process described in Example 2 with 11.5 par-ts of 6-chlo r-ben' zanthrone instead of 6-methyl-benzanthrone,

the crude product forms a reddish yellowpowder melting at 300to 305 C. and form ing an intensely red solution with concentrated sulphuric acid. By recrystallization from xylene G-chlor-22-dibenzanthronyl is obtained in the form of glittering yellowish brown leaflets melting at 312 to 314 C.

lVhen employing 7 chlor-benzanthrone instead of 6-chlor-benzanthrone, "('-chlo r-2.2-

dibenzanthronyl melting at 305 C. is obtained.

' Example 4 A mixture of 10 parts of crystallized benzanthrone and 13 parts of crystallized 2.6-dichlor-benzanthrone is introduced at C. in a current of nitrogen into a suspension of 1'? parts of. potassium anilide (prepared from 5.1 parts of potassium) in 200 parts of anhydrous aniline. The temperature is raised thereby to 8 C. and the color of the mixture turns brownish red. The mass is stirred for about 3hours at the said temperature and poured into dilute hydrochloric acid. The orange colored reaction product is treated with hot acetone until practically all soluble matter is dissolved. The-crudeproduct is twice recrystallized from boiling xylene. It is identical with the 6-chlor-2.2-dibenzanthronyl described in Example 3.

Example A mixture of 13 parts of crystallized 2.7- dichlor-benzanthrone (melting point 278.? G.) and 11.5 parts of crystallized 7-chlorbenzanthrone (melting point 182 to 184 C.) is introduced at C. in a current of nitrogen into a suspension of 15 parts of sodium anilide in 200 parts of anhydrous aniline. The temperatureis raised to 14 C. The mass is stirred for some hours-until the reaction is eomplete and poured into dilute hydrochloric acid. The mixture is filtered and the residue is dried. The orange colored crude product so obtained melts at 310 to 315 C. and can be obtained in a practically pure state by treatment with acetone.' By recrystallization from dichlor-benzene 7.7

dichlor-22-dibenzai1thronyl is obtainedin the form of small yellowish brown crystals melting above 370 C. and dissolving in concentrated sulphuric acid with red color.

In a similar manner, 6.6".-dich1or 2.2'-dibenzanthronyl melting abovef370 C. is obtained from 2.6-dichlor-benzanthrone and 6- chlo'r-b'enzanthrone.

Emample,

parts of isopropyl alcohol are caused to run at 0 to 5 G. into a suspension of parts of powdered potassium hydroxide, 10.8 parts of 2-chlor-benzanthrone and 10 parts of 6-me thyl-benzanthrone in 300 parts of toluene while excluding air. The mixture is stirred atvthe said temperature until the reaction is complete. The mixture is freed from toluene by distillation with steam and the productis purified by removing the alka line solution by'filtration by washing with suitable solvents, for example acetone or pyridine. It forms. greenish'yellow powder melting at 313 to 317 After recrystallization from trichlor=benzene thejG-niethyl- 2.2-dibenzanthronyl identical with that describedin Example 2 melts at 330 to 331 C.

This application is a divisional application of our copending' application 'Ser. No.'114,011, filed June 5,1926;

What we claim-is v1. As new? articles ofmanufacture, practically pure 2.2-dibenzanthronyls in which one of the benzanthrone radicles is 'substi tuted by a methyl group.

2. As a new article of manufacture, 6-.

methyl 22-dibenzanthronyl; In testimony whereof we affix our signatures.

ARTHUR LUTTRINGHAUS. HUGO WOLFE." HEINRICH NERESHEIJl IEB. 

